This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

Gum Arabic (acacia Senegal) is a complex polysaccharide indigestible to both humans
and animals. It has been considered as a safe dietary fiber by the United States,
Food and Drug Administration (FDA) since the 1970s. Although its effects were extensively
studied in animals, there is paucity of data regarding its quantified use in humans.
This study was conducted to determine effects of regular Gum Arabic (GA) ingestion
on body mass index and body fat percentage among healthy adult females.

Methods

A two-arm randomized, placebo controlled, double-blind trial was conducted in the
Department of Physiology at the Khartoum University. A total of 120 healthy females
completed the study. They were divided to two groups: A test group of 60 volunteers
receiving GA (30 gm /day) for 6 weeks and a placebo group of 60 volunteers receiving
pectin (1 gm/day) for the same period of time. Weight and height were measured before
and after intervention using standardized height and weight scales. Skin fold thickness
was measured using Harpenden Skin fold caliper. Fat percentage was calculated using
Jackson and Pollock 7 caliper method and Siri equation.

Results

Pre and post analysis among the study group showed significant reduction in BMI by
0.32 (95% CI: 0.17 to 0.47; P<0.0001) and body fat percentage by 2.18% (95% CI: 1.54
to 2.83; P<0.0001) following regular intake of 30 gm /day Gum Arabic for six weeks.
Side effects caused by GA ingestion were experienced only in the first week. They
included unfavorable viscous sensation in the mouth, early morning nausea, mild diarrhea
and bloating abdomen.

Conclusions

GA ingestion causes significant reduction in BMI and body fat percentage among healthy
adult females. The effect could be exploited in the treatment of obesity.

Keywords:

Gum Arabic; Obesity; BMI; Body fat percentage

Introduction

Gum Arabic (GA) is derived from exudates of Acacia senegal or Acacia seyal trees.
It consists of a mixture of polysaccharides (major component) plus oligosaccharides
and glycoproteins [1,2]; however, its composition can vary with its source, climate and soil. Sudan is the
world′s largest producer, followed by many other African countries. It readily dissolves
in water to form solutions characterized by low viscosity. This allows its use in
various applications [3]. It is used as an emulsifier, thickening agent and flavor stabilizer in both the
pharmaceutical and food industries. It is also used in textile, pottery and cosmetics
industries. The FAO/WHO Joint Expert Committee for Food Additives defined it as a
dried exudation obtained from the stems of A. Senegal or closely related species of
Acacia [4].

Gum Arabic was evaluated for acceptable daily intake for man by the Joint FAO/WHO
Expert Committee on Food Additives since 1969 [5]; however, Sudanese people in Western Sudan had been using it for long time without
limitations. It is indigestible to both humans and animals, not degraded in the intestine,
but fermented in the colon to give short-chain fatty acids, leading to a large range
of possible health benefits [6]. One of these benefits is its prebiotic effect [7,8]. It has been claimed that four week supplementation with Gum Arabic (10 g/day) led
to significant increases in Bifidobacteria, Lactobacteria, and Bacteriodes indicating
a prebiotic effect [8]. Other effects include reduction in plasma cholesterol level in animals and humans
[9], anticarcinogenic effect [10] and anti-oxidant effect [11,12] with a protective role against hepatic and cardiac toxicities. In addition to that,
it has been claimed that Gum Arabic alleviates effects of chronic renal failure in
humans; however, further studies are needed for confirmation [13-15].

Several epidemiological studies suggest that a high intake of dietary fiber, including
GA, is associated with beneficial effects on fat metabolism [14,16]. Dietary fiber promotes satiation and satiety, alter glycaemic index, affects gastric
emptying, gut hormone secretion and thus helps to manage weight [17]. Leptin promotes weight loss by two different mechanisms. It reduces appetite, and
thus food intake, and at the same time increases energy expenditure also dietary fiber
was inversely associated with leptin level in young Japanese adults [18,19]. In addition to that, a study has shown that GA inhibits intestinal glucose absorption
via interaction with membrane abundance of SGLT1 in mice [20].GA significantly blunted the increase in body weight, fasting plasma glucose and
fasting insulin concentrations during high fat diet.

Obesity is a well known risk factor for coronary heart disease, stroke, diabetes and
many other abnormalities, including cancer [21,22]. These complications depend not only on absolute amount of fat but also on its distribution.
Absolute total body fat and adipose tissue distribution are known to be associated
with cardiometabolic risk in adult females [23]. At least in theory, Gum Arabic can serve to reduce obesity and therefore prevent
associated complications in humans. The aim of this study is to determine the effects
of Gum Arabic ingestion on weight, body mass index and body fat percentage among healthy
adult females in randomized, placebo controlled and double-blind study.

Methods

This is a two-arm randomized, placebo controlled, double-blind study comparing an
intervention group receiving 30 gm of GA daily for 6 weeks with a control group receiving
a placebo for the same period of time. The study was conducted at the Department of
Physiology, Faculty of Medicine at the University of Khartoum during the period from
April to July 2011. All participants were female students from the University. Inclusion
criteria were age 17 years or above and healthy with no symptoms or signs of acute
or chronic medical illness. Exclusion criteria were age less than 17 years, past or
present history of metabolic, gastrointestinal, degenerative and/or inflammatory diseases,
smoking, drug abuse or alcohol consumption, use of corticosteroids or any other drug
that affects body weight, and history of Gum Arabic (GA) allergy. Participants were
asked to take habitually daily diet and to avoid exercise during the period of the
study.

To detect a reduction in body weight of 2 kilograms (SD 4 kilograms), with a two-sided
5% significance level and a power of 80%, a sample size of 60 subjects per group was
calculated based on normogram for comparison of means in two equal sized groups [24]. Random allocation was achieved by generating series of numbers by independent third-party
not associated with the study. Sealed boxes were prepared containing supplements package
of either intervention (Gum Arabic) or placebo (pectin). After the randomization sequence
generated the boxes containing the supplements was given to the blinded investigator
responsible for enrollment. Follow up assessments were undertaken by the chief investigator
who was also blinded to the randomization.

Eligible participants were 120 students. They were all enrolled and randomly allocated
into either intervention (n= 60) or placebo (n= 60) group by the blinded investigator
(Figure 1). Each participant was supplemented with a daily dose of either Gum Arabic or a placebo.
The dose of Gum Arabic was 30 g of 100% natural gum provided in a powder form by ″Dar
Savanna Ltd. Khartoum, Sudan″. Its quality was consistent to the requirements of Food
and Agriculture Organization of the United Nations (FAO) and British pharmacopoeia
(BP). The dose was divided in 5 sachets each containing 6 grams, consumed in two divided
doses; early morning dose of 3 sachets (18 gram) and evening dose of 2 sachets (12
gram) four hours after meal. The dose of placebo was 1 g of pectin given in two divided
doses in the same way. Each dose was reconstituted in 250 ml of water and shaken well
to ensure adequate mixing before intake.

Weight was measured by using digital physician′s scale to the nearest 0.1 kg. Height
was measured by using calibrated physician′s scale to the nearest 1 cm. BMI was calculated
by the standard formula: weight (kg) / height (m) 2.

Skin-fold thickness was measured using a harpenden Skin fold caliper. It was measured
at 7 different anatomical sites (chest, axilla, triceps, subscapular, abdomen, suprailium,
and thigh skin folds (mm). Three sets of measurements were averaged for each site.
The following Jackson- Pollock formula was used to calculate body density (BD) [25]. BD = 1.11200000 − 0.00043499(X) + 0.00000055(X) (X) − 0.00028826(A) (where X = Sum
of chest, axilla, triceps, subscapular, abdomen, suprailium, and thigh skin folds
in millimeters and A = age in years). Then the Siri equation was used for calculation
of body fat percentage from body density (% Fat = [(4.95/BD) − 4.5]100 [26].

Institutional review board approved this study. Appropriate written consents were
obtained from each student before enrollment in the study. All data were collected
prospectively by the researchers at the department. Double data entry and cross validation
were employed to ensure validity and quality of data. Data were analysed using STATA-10
program. The paired t test was used for analysis of pre and post-intervention data.
The independent sample t test was used for comparison between the intervention and
control groups. A p-value of less than 0.05 was considered statistically significant.

Discussion

The results showed that regular intake of 30 gm /day GA for six weeks resulted in
significant reduction in BMI and body fat percentage (P<0.0001) ,Changes in body weight
were reported to occur with many other fibers intake whether the fiber is obtained
from naturally high-fiber diet or when it is ingested in a form of a supplement [27].

The US Food and Drug Administration consider Gum Arabic (GA) as one of the safest
dietary fibres [28]. In this study 60 healthy female volunteers consumed GA without doubt as many Sudanese
used to ingest GA for both health benefits and nutritional purposes. Females were
selected as they are more concerned with aspects of their apperarance, particularly
weight [29]. The effects of GA on BMI and fat percentage were studied among these females.

Gum Arabic consumption seems to be an effective dietary strategy to prevent or treat
overweight with its several biological mechanisms [17], Obesity is a worldwide problem that is associated with many complications. Even
though regular exercise and dieting are effective and non-invasive measures used for
its treatment, compliance to these measures is limited [30]. The role of dietary fibers in prevention and treatment of obesity has been studied
in both humans and animals [27,31]. Although Gum Arabic influence on energy intake and body weight regulation remains
controversial. A growing body of scientific evidence indicates that GA ingestion causes
significant reduction in caloric intake with an increased subjective feeling of satiety
[32].

Many studies suggested a strong positive correlation between blood leptin concentration,
BMI and intake of dietary fiber, On the other hand, serum leptin concentrations were
not related to dietary patterns in the US population [33] and no significant correlation was found between leptin and dietary fiber [34].

In addition to these effects, dietary fibers including GA bind bile acids and diminish
their absorption in the terminal ileum [35]. Then in the large intestine, degradation of GA releases the sequestered bile acids
and the acidic pH generated during the fermentation process renders them insoluble
and promotes their excretion in stool [35]. This reduces their pool in the body and causes decreased fat digestion and absorption.
Similarly, the hepatic formation of new bile acids requires cholesterol. Thus, prolonged
ingestion of Gum Arabic may cause weight loss and reduction in cholesterol level in
plasma

In our study the effect reflected by a reduction in body weight by 1.24% from 72.25
to 71.43 ± 1.94 (mean ± SD) within the study group. A recent proposed mechanism by
which viscous dietary fibers were found to preserve lean body mass and reduce adiposity
is increased mitochondrial biogenesis and fatty acid oxidation by skeletal muscles
[36]. Gum Arabic mechanism is not yet fully elucidated, because of a small number of conducted
studies. This study highlights the effect of gum Arabic on BMI and fat %; it would
be wise to conduct a long-term studies, evaluating complete range of parameters with
different groups and doses to elucidate the mechanism of action of GA on reducing
obesity and its prevention.

Previous studies have shown that a daily dose of 30 g of GA can be tolerated by most
subjects and the main complaint was excessive flatulence [37]. However, this complaint was found to be mild, even at doses >50 g/day. In our study
symptoms were only experienced in the first week of supplementation and disappeared
later. Unfavorable viscous sensation in the mouth was the main complaint; however,
addition of a flavor to GA solution, as practiced by many of the volunteers, was found
to be useful. Diarrhea which was reported by 90% of cases could be the result of increased
intestinal motility due to the increase in bulk of stool. It is worth noting that
previous studies described GA as a treatment rather than a cause of diarrhea [38].

One of the limitations in our study is not measuring blood leptin concentration, due
to resource limitation. Another major limitation in this study is the high dose of
GA ingested daily by students in the group of cases compared with the low dose of
the placebo taken by the controls. However, our results do confirm that regular ingestion
of GA causes significant reduction of body mass index and body fat percentage among
subjects. This effect can be considered for treatment or prevention of obesity.

Conclusions

Gum Arabic ingestion causes significant reduction in BMI and body fat percentage among
healthy adult females. The effect could be exploited in the treatment of obesity.

Competing interests

The authors declare that they have no competing interests.

Authors’ contributions

RB has made enrolment and random allocation of participant, acquisition of measurements
and data, followed the study and drafted the manuscript. THM participated in the sequence
alignment, coordination and helped to draft the manuscript. KE designed and revised
the methodology, statically analyzed the data and revised the manuscript. RMB generated
the Idea and participated in designing the protocol and follow up. FL has been involved
in revising it critically for important intellectual content, drafted and revised
the manuscript. AMS made contributions to conception and design, directed the study,
drafted and revised the manuscript. All authors read and approved the final manuscript.

Castano B, Molina J, Cabrillana JM, Montoya-Alonso JA, Serra-Majem L: Variables predictive of adherence to diet and physical activity recommendations in
the treatment of obesity and overweight, in a group of Spanish subjects.